Table 4.

Number of sequences identified by the RDP classification algorithm*.

Level	Total Sequences	Average	SD	Fraction Above1000
phylum	12,656,355	23,656.74	18,811.06	0.96
class	12,586,705	23,526.55	18,747.07	0.96
order	12,550,239	23,458.39	18,703.47	0.96
family	12,369,533	23,120.62	18,402.11	0.96
genus	11,362,538	21,238.39	17,050.57	0.96
OTU	8,240,210	15,402.26	12,869.20	0.93

*The number of sequences identified by the RDP classification algorithm at a threshold of 50% (for phylum through genus) or were assigned to an OTU in QIIME 1.91. Almost all 226 case and 309 control samples had at least 1,000 sequences per sample (last column) and these samples were used for analysis at each phylogenetic level.